The present invention relates to a method for making silylalkenyl acetals. More particularly the present invention relates to a method for silylformylating alkynes with a silicon hydride, such as an alkoxy substituted silicon hydride and carbon monoxide in the presence of a rhodium catalyst.
A method for silylformylating alkynes is shown by Matsuda et al, JACS 1989, 111, 2332-2333. An alkyne is reacted with carbon monoxide and dimethylphenylsilane in the presence of a Rh.sub.4 (CO).sub.12 catalyst. A solution of the catalyst in benzene is used at a temperature of 100.degree. C. and a pressure of 30 Kg/cm.sup.2. Although the Matsuda et al method can be used to make various silylformylated alkenes, its scope is limited because it uses silicon hydride reactants which are substituted with non-functional radicals, i.e., hydrocarbon radicals attached to silicon by carbon-silicon bonds.
It is generally known that during the silylformylation of alkynes with a silicon hydride and carbon monoxide in the presence of a Group VIII metal catalyst, that a competing hydrosilylation reaction can occur. The silicon hydride, for example, can react with the silylalkenyl hydroformylated reaction product normally formed during the silylformylation reaction. In instances where functional silanes are used, such as halosilanes, hydrosilylation can be a significant side reaction which can drastically reduce the yield of the desired silylalkenyl reaction product.
It would be desirable therefore to provide a method for silylformylating alkynes utilizing silanes having functional groups in place of inert hydrocarbon radicals attached to silicon by carbon silicon bonds. Such novel silylformylated reaction products of alkynes would provide silanes having reactive functional groups which would enhance the utility of such materials as intermediates in chemical synthesis.